5,938 research outputs found
OS diversity for intrusion tolerance: Myth or reality?
One of the key benefits of using intrusion-tolerant systems is the possibility of ensuring correct behavior in the presence of attacks and intrusions. These security gains are directly dependent on the components exhibiting failure diversity. To what extent failure diversity is observed in practical deployment depends on how diverse are the components that constitute the system. In this paper we present a study with operating systems (OS) vulnerability data from the NIST National Vulnerability Database. We have analyzed the vulnerabilities of 11 different OSes over a period of roughly 15 years, to check how many of these vulnerabilities occur in more than one OS. We found this number to be low for several combinations of OSes. Hence, our analysis provides a strong indication that building a system with diverse OSes may be a useful technique to improve its intrusion tolerance capabilities
Volatiles and refratories in solar analogs: no terrestial planet connection
We have analysed very high-quality HARPS and UVES spectra of 95 solar
analogs, 24 hosting planets and 71 without detected planets, to search for any
possible signature of terrestial planets in the chemical abundances of volatile
and refractory elements with respect to the solar abundances. We demonstrate
that stars with and without planets in this sample show similar mean abundance
ratios, in particular, a sub-sample of 14 planet-host and 14 "single" solar
analogs in the metallicity range 0.14<[Fe/H]<0.36. In addition, two of the
planetary systems in this sub-sample, containing each of them a
super-Earth-like planet with masses in the range ~ 7-11 Earth masses, have
different volatile-to-refratory abundance ratios to what would be expected from
the presence of a terrestial planets. Finally, we check that after removing the
Galactic chemical evolution effects any possible difference in mean abundances,
with respect to solar values, of refratory and volatile elements practically
dissappears.Comment: 2 pages, 2 figures, to appear in the proceedings of the 276th IAU
Symposium "The Astrophysics of Planetary Systems
Sistema de biossorção produzido a partir de biofilmes suportados em zeólito faujasite (FAU), processo para a obtenção e sua utilização na remoção de crómio hexavalente (Cr(VI))
A presente invenção refere-se a um sistema de biossorção composto por um biofilme bacteriano suportado em zeólitos sintéticos, com utilização em vários tipos de indústrias para remoção do crómio hexavalente, através da retenção dos iões metálicos no biofilme, em soluções com concentrações entre 50 e 250 mgCr/l, processo para a sua obtenção e respectivas utilizações. Este processo consiste na obtenção de um biofilme bacteriano de arthrobacter viscosus, suportado num zeólito faujasite (FAU). O biofilme promove a redução de Cr(VI) a Cr(III) e, posteriormente, o Cr(III) é fixado no zeólito por permuta iónica. Várias técnicas de caracterização, como métodos espectroscópicos (FTIR e ICP-AES), análise superficial (XRD e SEM) e análise térmica (TGA), demonstram que o processo de biossorção não modifica a morfologia ou estrutura do zeólito FAU. O sistema de biossorção, e respectivo processo de fixação de crómio hexavalente em zeólitos faujasite (FAU), pode ser aplicável ao tratamento de águas residuais, industriais, mineiras ou agrícolas, para remoção do crómio hexavalente
Infantile Cystinosis
Infantile cystinosis is a rare disorder which leftuntreated results in end -stage renal disease early in life. Together with dehydration and electrolyte imbalance
due to renal tubular Fanconi syndrome, endstage renal disease used to be the leading cause of death in children with cystinosis. Specific therapy with cysteamine (cystine -depleting agent) has changed the course of this disease. Instead of being
fatal in childhood, it can nowadays be considered a multisystemic adult disorder. The authors report a case of a child diagnosed with Fanconi syndrome at 14 months of age and infantile cystinosis at 19
months of age in whom oral cysteamine treatment led to a good outcome during childhood
Imunodeficiência Combinada Grave – O Diagnóstico Precoce é Importante?
Introdução: Os doentes com Imunodeficiência Combinada Grave (SCID) não diagnosticados evoluem inexoravelmente para a morte no primeiro ano de vida. Um elevado índice de suspeição é fundamental para o diagnóstico precoce, o factor mais importante para a sobrevida destas crianças.
Objectivo: Apresentam-se três casos clínicos ilustrativos da importância da precocidade
diagnóstica no prognóstico final.
Casos clínicos: Caso clínico 1: Lactente do sexo masculino, com antecedentes de
infecções respiratórias de repetição, internado aos sete meses na UCIP do HDE por
pneumonia a Adenovírus com insuficiência respiratória. Necessitou de ventilação
mecânica e de duas transfusões de concentrado eritrocitário na primeira semana de internamento. Teve exantema exuberante, interpretado como toxidermia. Evoluiu para
doença pulmonar sequelar grave. Aos nove meses foi feito o diagnóstico de SCID
hipomorfa com doença do enxerto contra o hospedeiro pós-transfusional, controlada
com imunossupressão (ciclosporina e glucocorticoides). Não foi transplantado com
células progenitoras hematopoiéticas por não reunir condições clínicas. Na sequência de
uma intercorrência respiratória veio a falecer aos 14 meses. Caso clínico 2: Lactente do sexo masculino, internado aos 6 meses no HDE por pneumonia intersticial
hipoxemiante. Isolado P. jiroveci no lavado bronco-alveolar e feito o diagnóstico
presuntivo de BCGite disseminado em criança com SCID T-B+NK-. Após estabilização
clínica e esplenectomia foi transplantado com células progenitoras hematopoiéticas de
dador fenoidêntico não aparentado. Dada a BCGite disseminada necessitou de vários
ciclos de infusão de células do dador para uma reconstituição imunitária lenta e
progressiva. Seis meses pós-transplante está clinicamente bem, com quimerismo
linfóide T e NK completo. Caso clínico 3: Lactente do sexo masculino, internado aos
17 dias de vida por infecção respiratória alta e bacteriémia a M. catarrhalis. Reinternado quinze dias depois por sépsis a MRSA e linfopénia. A avaliação efectuada
permitiu o diagnóstico de SCID T-B+NK- por defeito na cadeia gamma comum.
Transplantado com células progenitoras hematopoiéticas de dador genoidêntico aos 4
meses, sem condicionamento. Clinicamente bem, seis meses pós-transplante, com
reconstituição imunitária satisfatória.
Conclusão: Esta doença tem uma prevalência não negligenciável e apenas com elevado
indice de suspeição se pode estabelecer um plano de tratamento eficaz
Estimation of the finite right endpoint in the Gumbel domain
A simple estimator for the finite right endpoint of a distribution function in the Gumbel max-domain of attraction is proposed. Large sample properties such as consistency and the asymptotic distribution are derived. A simulation study is presented
Monoclonal IgG Kappa Gammopathy Previous to Hematopoietic Stem Cell Transplantation in an Infant with Severe Combined Immunodeficiency
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Norovírus Associated Encephalopathy
clinical presentation is self limited. It is classified into five groups (genogroups I through V). There are numerous reports of neurologic complications, namely afebrile seizures, but only two reports of associated encephalopathy.
Case Report: A 12 month old girl with previous history of a pneumonia treated with amoxicillin-clavulanic acid and clarythromycin, presented in our emergency department with strabismus, ataxia for 3 days, later associated with vomiting and diarrhea. On admission she had ataxia and an episode of strabismus, but her later neurologic exam was normal.
Laboratory data revealed: 10,9 g/dL hemoglobin, 11.200/μL leukocytes, 29,1% neutrophils and 65,2% lymphocytes, 488.000/μL platelets and negative CRP.
The brain MRI showed middle ear, maxillary sinus and ethmoidal opacification, with no other abnormalities.
During the first day of admission she had a tonic (?) seizure for 20 minutes.
CSF analysis showed 5,6 cells/μL, 100% lymphocytes, 80 mg/dL glucose and 154,1 mg/dL protein.
The EEG revealed short duration paroxystic activity located to the vertex.
She was treated with acyclovir, ciprofloxacin, cefthriaxone and phenytoin. Her symptoms resolved by the third day of admission.
Blood samples were tested for numerous pathogens, including serology for Borrelia, which was positive for IgG but negative for IgM. Fecal sample analysis revealed positive PCR for norovirus, although it was negative in CSF samples. IL-6 was measured in the CSF and was negative (5,8 pg/mL).
She had a history of recurrent otitis media and pernieal candidiasis, which led to a detailed immune function study, which showed Immunology tests revealed diminished IgA (< 0,244 g/L) and absent antibody response to vaccinations. Since she was only 13 months old when she was tested, only follow up will determine the relevance of these values.
Follow up at two years of age showed no delays and a normal development.
Conclusion: Norovirus encephalitis is a rare entity, although gastrointestinal infection with this agent is relatively common. Here we present a case of a probable norovirus associated encephalopathy, although PCR for norovirus was negative in CSF samples and there was no CSF cytokine increase. It was not associated with adverse neurologic outcome and so far her development is normal, unlike the evolution described in previous case reports
Hamiltonian symplectic embedding of the massive noncommutative U(1) Theory
We show that the massive noncommutative U(1) theory is embedded in a gauge
theory using an alternative systematic way, which is based on the symplectic
framework. The embedded Hamiltonian density is obtained after a finite number
of steps in the iterative symplectic process, oppositely to the result proposed
using the BFFT formalism. This alternative formalism of embedding shows how to
get a set of dynamically equivalent embedded Hamiltonian densities.Comment: 16 pages, no figures, revtex4, corrected version, references
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